1//===-- Execution.cpp - Implement code to simulate the program ------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file contains the actual instruction interpreter.
11//
12//===----------------------------------------------------------------------===//
13
14#define DEBUG_TYPE "interpreter"
15#include "Interpreter.h"
16#include "llvm/Constants.h"
17#include "llvm/DerivedTypes.h"
18#include "llvm/Instructions.h"
19#include "llvm/CodeGen/IntrinsicLowering.h"
20#include "llvm/Support/GetElementPtrTypeIterator.h"
21#include "llvm/ADT/APInt.h"
22#include "llvm/ADT/Statistic.h"
23#include "llvm/Support/CommandLine.h"
24#include "llvm/Support/Debug.h"
25#include "llvm/Support/ErrorHandling.h"
26#include "llvm/Support/MathExtras.h"
27#include <algorithm>
28#include <cmath>
29using namespace llvm;
30
31STATISTIC(NumDynamicInsts, "Number of dynamic instructions executed");
32
33static cl::opt<bool> PrintVolatile("interpreter-print-volatile", cl::Hidden,
34          cl::desc("make the interpreter print every volatile load and store"));
35
36//===----------------------------------------------------------------------===//
37//                     Various Helper Functions
38//===----------------------------------------------------------------------===//
39
40static void SetValue(Value *V, GenericValue Val, ExecutionContext &SF) {
41  SF.Values[V] = Val;
42}
43
44//===----------------------------------------------------------------------===//
45//                    Binary Instruction Implementations
46//===----------------------------------------------------------------------===//
47
48#define IMPLEMENT_BINARY_OPERATOR(OP, TY) \
49   case Type::TY##TyID: \
50     Dest.TY##Val = Src1.TY##Val OP Src2.TY##Val; \
51     break
52
53static void executeFAddInst(GenericValue &Dest, GenericValue Src1,
54                            GenericValue Src2, Type *Ty) {
55  switch (Ty->getTypeID()) {
56    IMPLEMENT_BINARY_OPERATOR(+, Float);
57    IMPLEMENT_BINARY_OPERATOR(+, Double);
58  default:
59    dbgs() << "Unhandled type for FAdd instruction: " << *Ty << "\n";
60    llvm_unreachable(0);
61  }
62}
63
64static void executeFSubInst(GenericValue &Dest, GenericValue Src1,
65                            GenericValue Src2, Type *Ty) {
66  switch (Ty->getTypeID()) {
67    IMPLEMENT_BINARY_OPERATOR(-, Float);
68    IMPLEMENT_BINARY_OPERATOR(-, Double);
69  default:
70    dbgs() << "Unhandled type for FSub instruction: " << *Ty << "\n";
71    llvm_unreachable(0);
72  }
73}
74
75static void executeFMulInst(GenericValue &Dest, GenericValue Src1,
76                            GenericValue Src2, Type *Ty) {
77  switch (Ty->getTypeID()) {
78    IMPLEMENT_BINARY_OPERATOR(*, Float);
79    IMPLEMENT_BINARY_OPERATOR(*, Double);
80  default:
81    dbgs() << "Unhandled type for FMul instruction: " << *Ty << "\n";
82    llvm_unreachable(0);
83  }
84}
85
86static void executeFDivInst(GenericValue &Dest, GenericValue Src1,
87                            GenericValue Src2, Type *Ty) {
88  switch (Ty->getTypeID()) {
89    IMPLEMENT_BINARY_OPERATOR(/, Float);
90    IMPLEMENT_BINARY_OPERATOR(/, Double);
91  default:
92    dbgs() << "Unhandled type for FDiv instruction: " << *Ty << "\n";
93    llvm_unreachable(0);
94  }
95}
96
97static void executeFRemInst(GenericValue &Dest, GenericValue Src1,
98                            GenericValue Src2, Type *Ty) {
99  switch (Ty->getTypeID()) {
100  case Type::FloatTyID:
101    Dest.FloatVal = fmod(Src1.FloatVal, Src2.FloatVal);
102    break;
103  case Type::DoubleTyID:
104    Dest.DoubleVal = fmod(Src1.DoubleVal, Src2.DoubleVal);
105    break;
106  default:
107    dbgs() << "Unhandled type for Rem instruction: " << *Ty << "\n";
108    llvm_unreachable(0);
109  }
110}
111
112#define IMPLEMENT_INTEGER_ICMP(OP, TY) \
113   case Type::IntegerTyID:  \
114      Dest.IntVal = APInt(1,Src1.IntVal.OP(Src2.IntVal)); \
115      break;
116
117// Handle pointers specially because they must be compared with only as much
118// width as the host has.  We _do not_ want to be comparing 64 bit values when
119// running on a 32-bit target, otherwise the upper 32 bits might mess up
120// comparisons if they contain garbage.
121#define IMPLEMENT_POINTER_ICMP(OP) \
122   case Type::PointerTyID: \
123      Dest.IntVal = APInt(1,(void*)(intptr_t)Src1.PointerVal OP \
124                            (void*)(intptr_t)Src2.PointerVal); \
125      break;
126
127static GenericValue executeICMP_EQ(GenericValue Src1, GenericValue Src2,
128                                   Type *Ty) {
129  GenericValue Dest;
130  switch (Ty->getTypeID()) {
131    IMPLEMENT_INTEGER_ICMP(eq,Ty);
132    IMPLEMENT_POINTER_ICMP(==);
133  default:
134    dbgs() << "Unhandled type for ICMP_EQ predicate: " << *Ty << "\n";
135    llvm_unreachable(0);
136  }
137  return Dest;
138}
139
140static GenericValue executeICMP_NE(GenericValue Src1, GenericValue Src2,
141                                   Type *Ty) {
142  GenericValue Dest;
143  switch (Ty->getTypeID()) {
144    IMPLEMENT_INTEGER_ICMP(ne,Ty);
145    IMPLEMENT_POINTER_ICMP(!=);
146  default:
147    dbgs() << "Unhandled type for ICMP_NE predicate: " << *Ty << "\n";
148    llvm_unreachable(0);
149  }
150  return Dest;
151}
152
153static GenericValue executeICMP_ULT(GenericValue Src1, GenericValue Src2,
154                                    Type *Ty) {
155  GenericValue Dest;
156  switch (Ty->getTypeID()) {
157    IMPLEMENT_INTEGER_ICMP(ult,Ty);
158    IMPLEMENT_POINTER_ICMP(<);
159  default:
160    dbgs() << "Unhandled type for ICMP_ULT predicate: " << *Ty << "\n";
161    llvm_unreachable(0);
162  }
163  return Dest;
164}
165
166static GenericValue executeICMP_SLT(GenericValue Src1, GenericValue Src2,
167                                    Type *Ty) {
168  GenericValue Dest;
169  switch (Ty->getTypeID()) {
170    IMPLEMENT_INTEGER_ICMP(slt,Ty);
171    IMPLEMENT_POINTER_ICMP(<);
172  default:
173    dbgs() << "Unhandled type for ICMP_SLT predicate: " << *Ty << "\n";
174    llvm_unreachable(0);
175  }
176  return Dest;
177}
178
179static GenericValue executeICMP_UGT(GenericValue Src1, GenericValue Src2,
180                                    Type *Ty) {
181  GenericValue Dest;
182  switch (Ty->getTypeID()) {
183    IMPLEMENT_INTEGER_ICMP(ugt,Ty);
184    IMPLEMENT_POINTER_ICMP(>);
185  default:
186    dbgs() << "Unhandled type for ICMP_UGT predicate: " << *Ty << "\n";
187    llvm_unreachable(0);
188  }
189  return Dest;
190}
191
192static GenericValue executeICMP_SGT(GenericValue Src1, GenericValue Src2,
193                                    Type *Ty) {
194  GenericValue Dest;
195  switch (Ty->getTypeID()) {
196    IMPLEMENT_INTEGER_ICMP(sgt,Ty);
197    IMPLEMENT_POINTER_ICMP(>);
198  default:
199    dbgs() << "Unhandled type for ICMP_SGT predicate: " << *Ty << "\n";
200    llvm_unreachable(0);
201  }
202  return Dest;
203}
204
205static GenericValue executeICMP_ULE(GenericValue Src1, GenericValue Src2,
206                                    Type *Ty) {
207  GenericValue Dest;
208  switch (Ty->getTypeID()) {
209    IMPLEMENT_INTEGER_ICMP(ule,Ty);
210    IMPLEMENT_POINTER_ICMP(<=);
211  default:
212    dbgs() << "Unhandled type for ICMP_ULE predicate: " << *Ty << "\n";
213    llvm_unreachable(0);
214  }
215  return Dest;
216}
217
218static GenericValue executeICMP_SLE(GenericValue Src1, GenericValue Src2,
219                                    Type *Ty) {
220  GenericValue Dest;
221  switch (Ty->getTypeID()) {
222    IMPLEMENT_INTEGER_ICMP(sle,Ty);
223    IMPLEMENT_POINTER_ICMP(<=);
224  default:
225    dbgs() << "Unhandled type for ICMP_SLE predicate: " << *Ty << "\n";
226    llvm_unreachable(0);
227  }
228  return Dest;
229}
230
231static GenericValue executeICMP_UGE(GenericValue Src1, GenericValue Src2,
232                                    Type *Ty) {
233  GenericValue Dest;
234  switch (Ty->getTypeID()) {
235    IMPLEMENT_INTEGER_ICMP(uge,Ty);
236    IMPLEMENT_POINTER_ICMP(>=);
237  default:
238    dbgs() << "Unhandled type for ICMP_UGE predicate: " << *Ty << "\n";
239    llvm_unreachable(0);
240  }
241  return Dest;
242}
243
244static GenericValue executeICMP_SGE(GenericValue Src1, GenericValue Src2,
245                                    Type *Ty) {
246  GenericValue Dest;
247  switch (Ty->getTypeID()) {
248    IMPLEMENT_INTEGER_ICMP(sge,Ty);
249    IMPLEMENT_POINTER_ICMP(>=);
250  default:
251    dbgs() << "Unhandled type for ICMP_SGE predicate: " << *Ty << "\n";
252    llvm_unreachable(0);
253  }
254  return Dest;
255}
256
257void Interpreter::visitICmpInst(ICmpInst &I) {
258  ExecutionContext &SF = ECStack.back();
259  Type *Ty    = I.getOperand(0)->getType();
260  GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
261  GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
262  GenericValue R;   // Result
263
264  switch (I.getPredicate()) {
265  case ICmpInst::ICMP_EQ:  R = executeICMP_EQ(Src1,  Src2, Ty); break;
266  case ICmpInst::ICMP_NE:  R = executeICMP_NE(Src1,  Src2, Ty); break;
267  case ICmpInst::ICMP_ULT: R = executeICMP_ULT(Src1, Src2, Ty); break;
268  case ICmpInst::ICMP_SLT: R = executeICMP_SLT(Src1, Src2, Ty); break;
269  case ICmpInst::ICMP_UGT: R = executeICMP_UGT(Src1, Src2, Ty); break;
270  case ICmpInst::ICMP_SGT: R = executeICMP_SGT(Src1, Src2, Ty); break;
271  case ICmpInst::ICMP_ULE: R = executeICMP_ULE(Src1, Src2, Ty); break;
272  case ICmpInst::ICMP_SLE: R = executeICMP_SLE(Src1, Src2, Ty); break;
273  case ICmpInst::ICMP_UGE: R = executeICMP_UGE(Src1, Src2, Ty); break;
274  case ICmpInst::ICMP_SGE: R = executeICMP_SGE(Src1, Src2, Ty); break;
275  default:
276    dbgs() << "Don't know how to handle this ICmp predicate!\n-->" << I;
277    llvm_unreachable(0);
278  }
279
280  SetValue(&I, R, SF);
281}
282
283#define IMPLEMENT_FCMP(OP, TY) \
284   case Type::TY##TyID: \
285     Dest.IntVal = APInt(1,Src1.TY##Val OP Src2.TY##Val); \
286     break
287
288static GenericValue executeFCMP_OEQ(GenericValue Src1, GenericValue Src2,
289                                   Type *Ty) {
290  GenericValue Dest;
291  switch (Ty->getTypeID()) {
292    IMPLEMENT_FCMP(==, Float);
293    IMPLEMENT_FCMP(==, Double);
294  default:
295    dbgs() << "Unhandled type for FCmp EQ instruction: " << *Ty << "\n";
296    llvm_unreachable(0);
297  }
298  return Dest;
299}
300
301static GenericValue executeFCMP_ONE(GenericValue Src1, GenericValue Src2,
302                                   Type *Ty) {
303  GenericValue Dest;
304  switch (Ty->getTypeID()) {
305    IMPLEMENT_FCMP(!=, Float);
306    IMPLEMENT_FCMP(!=, Double);
307
308  default:
309    dbgs() << "Unhandled type for FCmp NE instruction: " << *Ty << "\n";
310    llvm_unreachable(0);
311  }
312  return Dest;
313}
314
315static GenericValue executeFCMP_OLE(GenericValue Src1, GenericValue Src2,
316                                   Type *Ty) {
317  GenericValue Dest;
318  switch (Ty->getTypeID()) {
319    IMPLEMENT_FCMP(<=, Float);
320    IMPLEMENT_FCMP(<=, Double);
321  default:
322    dbgs() << "Unhandled type for FCmp LE instruction: " << *Ty << "\n";
323    llvm_unreachable(0);
324  }
325  return Dest;
326}
327
328static GenericValue executeFCMP_OGE(GenericValue Src1, GenericValue Src2,
329                                   Type *Ty) {
330  GenericValue Dest;
331  switch (Ty->getTypeID()) {
332    IMPLEMENT_FCMP(>=, Float);
333    IMPLEMENT_FCMP(>=, Double);
334  default:
335    dbgs() << "Unhandled type for FCmp GE instruction: " << *Ty << "\n";
336    llvm_unreachable(0);
337  }
338  return Dest;
339}
340
341static GenericValue executeFCMP_OLT(GenericValue Src1, GenericValue Src2,
342                                   Type *Ty) {
343  GenericValue Dest;
344  switch (Ty->getTypeID()) {
345    IMPLEMENT_FCMP(<, Float);
346    IMPLEMENT_FCMP(<, Double);
347  default:
348    dbgs() << "Unhandled type for FCmp LT instruction: " << *Ty << "\n";
349    llvm_unreachable(0);
350  }
351  return Dest;
352}
353
354static GenericValue executeFCMP_OGT(GenericValue Src1, GenericValue Src2,
355                                     Type *Ty) {
356  GenericValue Dest;
357  switch (Ty->getTypeID()) {
358    IMPLEMENT_FCMP(>, Float);
359    IMPLEMENT_FCMP(>, Double);
360  default:
361    dbgs() << "Unhandled type for FCmp GT instruction: " << *Ty << "\n";
362    llvm_unreachable(0);
363  }
364  return Dest;
365}
366
367#define IMPLEMENT_UNORDERED(TY, X,Y)                                     \
368  if (TY->isFloatTy()) {                                                 \
369    if (X.FloatVal != X.FloatVal || Y.FloatVal != Y.FloatVal) {          \
370      Dest.IntVal = APInt(1,true);                                       \
371      return Dest;                                                       \
372    }                                                                    \
373  } else if (X.DoubleVal != X.DoubleVal || Y.DoubleVal != Y.DoubleVal) { \
374    Dest.IntVal = APInt(1,true);                                         \
375    return Dest;                                                         \
376  }
377
378
379static GenericValue executeFCMP_UEQ(GenericValue Src1, GenericValue Src2,
380                                   Type *Ty) {
381  GenericValue Dest;
382  IMPLEMENT_UNORDERED(Ty, Src1, Src2)
383  return executeFCMP_OEQ(Src1, Src2, Ty);
384}
385
386static GenericValue executeFCMP_UNE(GenericValue Src1, GenericValue Src2,
387                                   Type *Ty) {
388  GenericValue Dest;
389  IMPLEMENT_UNORDERED(Ty, Src1, Src2)
390  return executeFCMP_ONE(Src1, Src2, Ty);
391}
392
393static GenericValue executeFCMP_ULE(GenericValue Src1, GenericValue Src2,
394                                   Type *Ty) {
395  GenericValue Dest;
396  IMPLEMENT_UNORDERED(Ty, Src1, Src2)
397  return executeFCMP_OLE(Src1, Src2, Ty);
398}
399
400static GenericValue executeFCMP_UGE(GenericValue Src1, GenericValue Src2,
401                                   Type *Ty) {
402  GenericValue Dest;
403  IMPLEMENT_UNORDERED(Ty, Src1, Src2)
404  return executeFCMP_OGE(Src1, Src2, Ty);
405}
406
407static GenericValue executeFCMP_ULT(GenericValue Src1, GenericValue Src2,
408                                   Type *Ty) {
409  GenericValue Dest;
410  IMPLEMENT_UNORDERED(Ty, Src1, Src2)
411  return executeFCMP_OLT(Src1, Src2, Ty);
412}
413
414static GenericValue executeFCMP_UGT(GenericValue Src1, GenericValue Src2,
415                                     Type *Ty) {
416  GenericValue Dest;
417  IMPLEMENT_UNORDERED(Ty, Src1, Src2)
418  return executeFCMP_OGT(Src1, Src2, Ty);
419}
420
421static GenericValue executeFCMP_ORD(GenericValue Src1, GenericValue Src2,
422                                     Type *Ty) {
423  GenericValue Dest;
424  if (Ty->isFloatTy())
425    Dest.IntVal = APInt(1,(Src1.FloatVal == Src1.FloatVal &&
426                           Src2.FloatVal == Src2.FloatVal));
427  else
428    Dest.IntVal = APInt(1,(Src1.DoubleVal == Src1.DoubleVal &&
429                           Src2.DoubleVal == Src2.DoubleVal));
430  return Dest;
431}
432
433static GenericValue executeFCMP_UNO(GenericValue Src1, GenericValue Src2,
434                                     Type *Ty) {
435  GenericValue Dest;
436  if (Ty->isFloatTy())
437    Dest.IntVal = APInt(1,(Src1.FloatVal != Src1.FloatVal ||
438                           Src2.FloatVal != Src2.FloatVal));
439  else
440    Dest.IntVal = APInt(1,(Src1.DoubleVal != Src1.DoubleVal ||
441                           Src2.DoubleVal != Src2.DoubleVal));
442  return Dest;
443}
444
445void Interpreter::visitFCmpInst(FCmpInst &I) {
446  ExecutionContext &SF = ECStack.back();
447  Type *Ty    = I.getOperand(0)->getType();
448  GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
449  GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
450  GenericValue R;   // Result
451
452  switch (I.getPredicate()) {
453  case FCmpInst::FCMP_FALSE: R.IntVal = APInt(1,false); break;
454  case FCmpInst::FCMP_TRUE:  R.IntVal = APInt(1,true); break;
455  case FCmpInst::FCMP_ORD:   R = executeFCMP_ORD(Src1, Src2, Ty); break;
456  case FCmpInst::FCMP_UNO:   R = executeFCMP_UNO(Src1, Src2, Ty); break;
457  case FCmpInst::FCMP_UEQ:   R = executeFCMP_UEQ(Src1, Src2, Ty); break;
458  case FCmpInst::FCMP_OEQ:   R = executeFCMP_OEQ(Src1, Src2, Ty); break;
459  case FCmpInst::FCMP_UNE:   R = executeFCMP_UNE(Src1, Src2, Ty); break;
460  case FCmpInst::FCMP_ONE:   R = executeFCMP_ONE(Src1, Src2, Ty); break;
461  case FCmpInst::FCMP_ULT:   R = executeFCMP_ULT(Src1, Src2, Ty); break;
462  case FCmpInst::FCMP_OLT:   R = executeFCMP_OLT(Src1, Src2, Ty); break;
463  case FCmpInst::FCMP_UGT:   R = executeFCMP_UGT(Src1, Src2, Ty); break;
464  case FCmpInst::FCMP_OGT:   R = executeFCMP_OGT(Src1, Src2, Ty); break;
465  case FCmpInst::FCMP_ULE:   R = executeFCMP_ULE(Src1, Src2, Ty); break;
466  case FCmpInst::FCMP_OLE:   R = executeFCMP_OLE(Src1, Src2, Ty); break;
467  case FCmpInst::FCMP_UGE:   R = executeFCMP_UGE(Src1, Src2, Ty); break;
468  case FCmpInst::FCMP_OGE:   R = executeFCMP_OGE(Src1, Src2, Ty); break;
469  default:
470    dbgs() << "Don't know how to handle this FCmp predicate!\n-->" << I;
471    llvm_unreachable(0);
472  }
473
474  SetValue(&I, R, SF);
475}
476
477static GenericValue executeCmpInst(unsigned predicate, GenericValue Src1,
478                                   GenericValue Src2, Type *Ty) {
479  GenericValue Result;
480  switch (predicate) {
481  case ICmpInst::ICMP_EQ:    return executeICMP_EQ(Src1, Src2, Ty);
482  case ICmpInst::ICMP_NE:    return executeICMP_NE(Src1, Src2, Ty);
483  case ICmpInst::ICMP_UGT:   return executeICMP_UGT(Src1, Src2, Ty);
484  case ICmpInst::ICMP_SGT:   return executeICMP_SGT(Src1, Src2, Ty);
485  case ICmpInst::ICMP_ULT:   return executeICMP_ULT(Src1, Src2, Ty);
486  case ICmpInst::ICMP_SLT:   return executeICMP_SLT(Src1, Src2, Ty);
487  case ICmpInst::ICMP_UGE:   return executeICMP_UGE(Src1, Src2, Ty);
488  case ICmpInst::ICMP_SGE:   return executeICMP_SGE(Src1, Src2, Ty);
489  case ICmpInst::ICMP_ULE:   return executeICMP_ULE(Src1, Src2, Ty);
490  case ICmpInst::ICMP_SLE:   return executeICMP_SLE(Src1, Src2, Ty);
491  case FCmpInst::FCMP_ORD:   return executeFCMP_ORD(Src1, Src2, Ty);
492  case FCmpInst::FCMP_UNO:   return executeFCMP_UNO(Src1, Src2, Ty);
493  case FCmpInst::FCMP_OEQ:   return executeFCMP_OEQ(Src1, Src2, Ty);
494  case FCmpInst::FCMP_UEQ:   return executeFCMP_UEQ(Src1, Src2, Ty);
495  case FCmpInst::FCMP_ONE:   return executeFCMP_ONE(Src1, Src2, Ty);
496  case FCmpInst::FCMP_UNE:   return executeFCMP_UNE(Src1, Src2, Ty);
497  case FCmpInst::FCMP_OLT:   return executeFCMP_OLT(Src1, Src2, Ty);
498  case FCmpInst::FCMP_ULT:   return executeFCMP_ULT(Src1, Src2, Ty);
499  case FCmpInst::FCMP_OGT:   return executeFCMP_OGT(Src1, Src2, Ty);
500  case FCmpInst::FCMP_UGT:   return executeFCMP_UGT(Src1, Src2, Ty);
501  case FCmpInst::FCMP_OLE:   return executeFCMP_OLE(Src1, Src2, Ty);
502  case FCmpInst::FCMP_ULE:   return executeFCMP_ULE(Src1, Src2, Ty);
503  case FCmpInst::FCMP_OGE:   return executeFCMP_OGE(Src1, Src2, Ty);
504  case FCmpInst::FCMP_UGE:   return executeFCMP_UGE(Src1, Src2, Ty);
505  case FCmpInst::FCMP_FALSE: {
506    GenericValue Result;
507    Result.IntVal = APInt(1, false);
508    return Result;
509  }
510  case FCmpInst::FCMP_TRUE: {
511    GenericValue Result;
512    Result.IntVal = APInt(1, true);
513    return Result;
514  }
515  default:
516    dbgs() << "Unhandled Cmp predicate\n";
517    llvm_unreachable(0);
518  }
519}
520
521void Interpreter::visitBinaryOperator(BinaryOperator &I) {
522  ExecutionContext &SF = ECStack.back();
523  Type *Ty    = I.getOperand(0)->getType();
524  GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
525  GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
526  GenericValue R;   // Result
527
528  switch (I.getOpcode()) {
529  case Instruction::Add:   R.IntVal = Src1.IntVal + Src2.IntVal; break;
530  case Instruction::Sub:   R.IntVal = Src1.IntVal - Src2.IntVal; break;
531  case Instruction::Mul:   R.IntVal = Src1.IntVal * Src2.IntVal; break;
532  case Instruction::FAdd:  executeFAddInst(R, Src1, Src2, Ty); break;
533  case Instruction::FSub:  executeFSubInst(R, Src1, Src2, Ty); break;
534  case Instruction::FMul:  executeFMulInst(R, Src1, Src2, Ty); break;
535  case Instruction::FDiv:  executeFDivInst(R, Src1, Src2, Ty); break;
536  case Instruction::FRem:  executeFRemInst(R, Src1, Src2, Ty); break;
537  case Instruction::UDiv:  R.IntVal = Src1.IntVal.udiv(Src2.IntVal); break;
538  case Instruction::SDiv:  R.IntVal = Src1.IntVal.sdiv(Src2.IntVal); break;
539  case Instruction::URem:  R.IntVal = Src1.IntVal.urem(Src2.IntVal); break;
540  case Instruction::SRem:  R.IntVal = Src1.IntVal.srem(Src2.IntVal); break;
541  case Instruction::And:   R.IntVal = Src1.IntVal & Src2.IntVal; break;
542  case Instruction::Or:    R.IntVal = Src1.IntVal | Src2.IntVal; break;
543  case Instruction::Xor:   R.IntVal = Src1.IntVal ^ Src2.IntVal; break;
544  default:
545    dbgs() << "Don't know how to handle this binary operator!\n-->" << I;
546    llvm_unreachable(0);
547  }
548
549  SetValue(&I, R, SF);
550}
551
552static GenericValue executeSelectInst(GenericValue Src1, GenericValue Src2,
553                                      GenericValue Src3) {
554  return Src1.IntVal == 0 ? Src3 : Src2;
555}
556
557void Interpreter::visitSelectInst(SelectInst &I) {
558  ExecutionContext &SF = ECStack.back();
559  GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
560  GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
561  GenericValue Src3 = getOperandValue(I.getOperand(2), SF);
562  GenericValue R = executeSelectInst(Src1, Src2, Src3);
563  SetValue(&I, R, SF);
564}
565
566
567//===----------------------------------------------------------------------===//
568//                     Terminator Instruction Implementations
569//===----------------------------------------------------------------------===//
570
571void Interpreter::exitCalled(GenericValue GV) {
572  // runAtExitHandlers() assumes there are no stack frames, but
573  // if exit() was called, then it had a stack frame. Blow away
574  // the stack before interpreting atexit handlers.
575  ECStack.clear();
576  runAtExitHandlers();
577  exit(GV.IntVal.zextOrTrunc(32).getZExtValue());
578}
579
580/// Pop the last stack frame off of ECStack and then copy the result
581/// back into the result variable if we are not returning void. The
582/// result variable may be the ExitValue, or the Value of the calling
583/// CallInst if there was a previous stack frame. This method may
584/// invalidate any ECStack iterators you have. This method also takes
585/// care of switching to the normal destination BB, if we are returning
586/// from an invoke.
587///
588void Interpreter::popStackAndReturnValueToCaller(Type *RetTy,
589                                                 GenericValue Result) {
590  // Pop the current stack frame.
591  ECStack.pop_back();
592
593  if (ECStack.empty()) {  // Finished main.  Put result into exit code...
594    if (RetTy && !RetTy->isVoidTy()) {          // Nonvoid return type?
595      ExitValue = Result;   // Capture the exit value of the program
596    } else {
597      memset(&ExitValue.Untyped, 0, sizeof(ExitValue.Untyped));
598    }
599  } else {
600    // If we have a previous stack frame, and we have a previous call,
601    // fill in the return value...
602    ExecutionContext &CallingSF = ECStack.back();
603    if (Instruction *I = CallingSF.Caller.getInstruction()) {
604      // Save result...
605      if (!CallingSF.Caller.getType()->isVoidTy())
606        SetValue(I, Result, CallingSF);
607      if (InvokeInst *II = dyn_cast<InvokeInst> (I))
608        SwitchToNewBasicBlock (II->getNormalDest (), CallingSF);
609      CallingSF.Caller = CallSite();          // We returned from the call...
610    }
611  }
612}
613
614void Interpreter::visitReturnInst(ReturnInst &I) {
615  ExecutionContext &SF = ECStack.back();
616  Type *RetTy = Type::getVoidTy(I.getContext());
617  GenericValue Result;
618
619  // Save away the return value... (if we are not 'ret void')
620  if (I.getNumOperands()) {
621    RetTy  = I.getReturnValue()->getType();
622    Result = getOperandValue(I.getReturnValue(), SF);
623  }
624
625  popStackAndReturnValueToCaller(RetTy, Result);
626}
627
628void Interpreter::visitUnwindInst(UnwindInst &I) {
629  // Unwind stack
630  Instruction *Inst;
631  do {
632    ECStack.pop_back();
633    if (ECStack.empty())
634      report_fatal_error("Empty stack during unwind!");
635    Inst = ECStack.back().Caller.getInstruction();
636  } while (!(Inst && isa<InvokeInst>(Inst)));
637
638  // Return from invoke
639  ExecutionContext &InvokingSF = ECStack.back();
640  InvokingSF.Caller = CallSite();
641
642  // Go to exceptional destination BB of invoke instruction
643  SwitchToNewBasicBlock(cast<InvokeInst>(Inst)->getUnwindDest(), InvokingSF);
644}
645
646void Interpreter::visitUnreachableInst(UnreachableInst &I) {
647  report_fatal_error("Program executed an 'unreachable' instruction!");
648}
649
650void Interpreter::visitBranchInst(BranchInst &I) {
651  ExecutionContext &SF = ECStack.back();
652  BasicBlock *Dest;
653
654  Dest = I.getSuccessor(0);          // Uncond branches have a fixed dest...
655  if (!I.isUnconditional()) {
656    Value *Cond = I.getCondition();
657    if (getOperandValue(Cond, SF).IntVal == 0) // If false cond...
658      Dest = I.getSuccessor(1);
659  }
660  SwitchToNewBasicBlock(Dest, SF);
661}
662
663void Interpreter::visitSwitchInst(SwitchInst &I) {
664  ExecutionContext &SF = ECStack.back();
665  Value* Cond = I.getCondition();
666  Type *ElTy = Cond->getType();
667  GenericValue CondVal = getOperandValue(Cond, SF);
668
669  // Check to see if any of the cases match...
670  BasicBlock *Dest = 0;
671  unsigned NumCases = I.getNumCases();
672  // Skip the first item since that's the default case.
673  for (unsigned i = 1; i < NumCases; ++i) {
674    GenericValue CaseVal = getOperandValue(I.getCaseValue(i), SF);
675    if (executeICMP_EQ(CondVal, CaseVal, ElTy).IntVal != 0) {
676      Dest = cast<BasicBlock>(I.getSuccessor(i));
677      break;
678    }
679  }
680  if (!Dest) Dest = I.getDefaultDest();   // No cases matched: use default
681  SwitchToNewBasicBlock(Dest, SF);
682}
683
684void Interpreter::visitIndirectBrInst(IndirectBrInst &I) {
685  ExecutionContext &SF = ECStack.back();
686  void *Dest = GVTOP(getOperandValue(I.getAddress(), SF));
687  SwitchToNewBasicBlock((BasicBlock*)Dest, SF);
688}
689
690
691// SwitchToNewBasicBlock - This method is used to jump to a new basic block.
692// This function handles the actual updating of block and instruction iterators
693// as well as execution of all of the PHI nodes in the destination block.
694//
695// This method does this because all of the PHI nodes must be executed
696// atomically, reading their inputs before any of the results are updated.  Not
697// doing this can cause problems if the PHI nodes depend on other PHI nodes for
698// their inputs.  If the input PHI node is updated before it is read, incorrect
699// results can happen.  Thus we use a two phase approach.
700//
701void Interpreter::SwitchToNewBasicBlock(BasicBlock *Dest, ExecutionContext &SF){
702  BasicBlock *PrevBB = SF.CurBB;      // Remember where we came from...
703  SF.CurBB   = Dest;                  // Update CurBB to branch destination
704  SF.CurInst = SF.CurBB->begin();     // Update new instruction ptr...
705
706  if (!isa<PHINode>(SF.CurInst)) return;  // Nothing fancy to do
707
708  // Loop over all of the PHI nodes in the current block, reading their inputs.
709  std::vector<GenericValue> ResultValues;
710
711  for (; PHINode *PN = dyn_cast<PHINode>(SF.CurInst); ++SF.CurInst) {
712    // Search for the value corresponding to this previous bb...
713    int i = PN->getBasicBlockIndex(PrevBB);
714    assert(i != -1 && "PHINode doesn't contain entry for predecessor??");
715    Value *IncomingValue = PN->getIncomingValue(i);
716
717    // Save the incoming value for this PHI node...
718    ResultValues.push_back(getOperandValue(IncomingValue, SF));
719  }
720
721  // Now loop over all of the PHI nodes setting their values...
722  SF.CurInst = SF.CurBB->begin();
723  for (unsigned i = 0; isa<PHINode>(SF.CurInst); ++SF.CurInst, ++i) {
724    PHINode *PN = cast<PHINode>(SF.CurInst);
725    SetValue(PN, ResultValues[i], SF);
726  }
727}
728
729//===----------------------------------------------------------------------===//
730//                     Memory Instruction Implementations
731//===----------------------------------------------------------------------===//
732
733void Interpreter::visitAllocaInst(AllocaInst &I) {
734  ExecutionContext &SF = ECStack.back();
735
736  Type *Ty = I.getType()->getElementType();  // Type to be allocated
737
738  // Get the number of elements being allocated by the array...
739  unsigned NumElements =
740    getOperandValue(I.getOperand(0), SF).IntVal.getZExtValue();
741
742  unsigned TypeSize = (size_t)TD.getTypeAllocSize(Ty);
743
744  // Avoid malloc-ing zero bytes, use max()...
745  unsigned MemToAlloc = std::max(1U, NumElements * TypeSize);
746
747  // Allocate enough memory to hold the type...
748  void *Memory = malloc(MemToAlloc);
749
750  DEBUG(dbgs() << "Allocated Type: " << *Ty << " (" << TypeSize << " bytes) x "
751               << NumElements << " (Total: " << MemToAlloc << ") at "
752               << uintptr_t(Memory) << '\n');
753
754  GenericValue Result = PTOGV(Memory);
755  assert(Result.PointerVal != 0 && "Null pointer returned by malloc!");
756  SetValue(&I, Result, SF);
757
758  if (I.getOpcode() == Instruction::Alloca)
759    ECStack.back().Allocas.add(Memory);
760}
761
762// getElementOffset - The workhorse for getelementptr.
763//
764GenericValue Interpreter::executeGEPOperation(Value *Ptr, gep_type_iterator I,
765                                              gep_type_iterator E,
766                                              ExecutionContext &SF) {
767  assert(Ptr->getType()->isPointerTy() &&
768         "Cannot getElementOffset of a nonpointer type!");
769
770  uint64_t Total = 0;
771
772  for (; I != E; ++I) {
773    if (StructType *STy = dyn_cast<StructType>(*I)) {
774      const StructLayout *SLO = TD.getStructLayout(STy);
775
776      const ConstantInt *CPU = cast<ConstantInt>(I.getOperand());
777      unsigned Index = unsigned(CPU->getZExtValue());
778
779      Total += SLO->getElementOffset(Index);
780    } else {
781      SequentialType *ST = cast<SequentialType>(*I);
782      // Get the index number for the array... which must be long type...
783      GenericValue IdxGV = getOperandValue(I.getOperand(), SF);
784
785      int64_t Idx;
786      unsigned BitWidth =
787        cast<IntegerType>(I.getOperand()->getType())->getBitWidth();
788      if (BitWidth == 32)
789        Idx = (int64_t)(int32_t)IdxGV.IntVal.getZExtValue();
790      else {
791        assert(BitWidth == 64 && "Invalid index type for getelementptr");
792        Idx = (int64_t)IdxGV.IntVal.getZExtValue();
793      }
794      Total += TD.getTypeAllocSize(ST->getElementType())*Idx;
795    }
796  }
797
798  GenericValue Result;
799  Result.PointerVal = ((char*)getOperandValue(Ptr, SF).PointerVal) + Total;
800  DEBUG(dbgs() << "GEP Index " << Total << " bytes.\n");
801  return Result;
802}
803
804void Interpreter::visitGetElementPtrInst(GetElementPtrInst &I) {
805  ExecutionContext &SF = ECStack.back();
806  SetValue(&I, executeGEPOperation(I.getPointerOperand(),
807                                   gep_type_begin(I), gep_type_end(I), SF), SF);
808}
809
810void Interpreter::visitLoadInst(LoadInst &I) {
811  ExecutionContext &SF = ECStack.back();
812  GenericValue SRC = getOperandValue(I.getPointerOperand(), SF);
813  GenericValue *Ptr = (GenericValue*)GVTOP(SRC);
814  GenericValue Result;
815  LoadValueFromMemory(Result, Ptr, I.getType());
816  SetValue(&I, Result, SF);
817  if (I.isVolatile() && PrintVolatile)
818    dbgs() << "Volatile load " << I;
819}
820
821void Interpreter::visitStoreInst(StoreInst &I) {
822  ExecutionContext &SF = ECStack.back();
823  GenericValue Val = getOperandValue(I.getOperand(0), SF);
824  GenericValue SRC = getOperandValue(I.getPointerOperand(), SF);
825  StoreValueToMemory(Val, (GenericValue *)GVTOP(SRC),
826                     I.getOperand(0)->getType());
827  if (I.isVolatile() && PrintVolatile)
828    dbgs() << "Volatile store: " << I;
829}
830
831//===----------------------------------------------------------------------===//
832//                 Miscellaneous Instruction Implementations
833//===----------------------------------------------------------------------===//
834
835void Interpreter::visitCallSite(CallSite CS) {
836  ExecutionContext &SF = ECStack.back();
837
838  // Check to see if this is an intrinsic function call...
839  Function *F = CS.getCalledFunction();
840  if (F && F->isDeclaration())
841    switch (F->getIntrinsicID()) {
842    case Intrinsic::not_intrinsic:
843      break;
844    case Intrinsic::vastart: { // va_start
845      GenericValue ArgIndex;
846      ArgIndex.UIntPairVal.first = ECStack.size() - 1;
847      ArgIndex.UIntPairVal.second = 0;
848      SetValue(CS.getInstruction(), ArgIndex, SF);
849      return;
850    }
851    case Intrinsic::vaend:    // va_end is a noop for the interpreter
852      return;
853    case Intrinsic::vacopy:   // va_copy: dest = src
854      SetValue(CS.getInstruction(), getOperandValue(*CS.arg_begin(), SF), SF);
855      return;
856    default:
857      // If it is an unknown intrinsic function, use the intrinsic lowering
858      // class to transform it into hopefully tasty LLVM code.
859      //
860      BasicBlock::iterator me(CS.getInstruction());
861      BasicBlock *Parent = CS.getInstruction()->getParent();
862      bool atBegin(Parent->begin() == me);
863      if (!atBegin)
864        --me;
865      IL->LowerIntrinsicCall(cast<CallInst>(CS.getInstruction()));
866
867      // Restore the CurInst pointer to the first instruction newly inserted, if
868      // any.
869      if (atBegin) {
870        SF.CurInst = Parent->begin();
871      } else {
872        SF.CurInst = me;
873        ++SF.CurInst;
874      }
875      return;
876    }
877
878
879  SF.Caller = CS;
880  std::vector<GenericValue> ArgVals;
881  const unsigned NumArgs = SF.Caller.arg_size();
882  ArgVals.reserve(NumArgs);
883  uint16_t pNum = 1;
884  for (CallSite::arg_iterator i = SF.Caller.arg_begin(),
885         e = SF.Caller.arg_end(); i != e; ++i, ++pNum) {
886    Value *V = *i;
887    ArgVals.push_back(getOperandValue(V, SF));
888  }
889
890  // To handle indirect calls, we must get the pointer value from the argument
891  // and treat it as a function pointer.
892  GenericValue SRC = getOperandValue(SF.Caller.getCalledValue(), SF);
893  callFunction((Function*)GVTOP(SRC), ArgVals);
894}
895
896void Interpreter::visitShl(BinaryOperator &I) {
897  ExecutionContext &SF = ECStack.back();
898  GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
899  GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
900  GenericValue Dest;
901  if (Src2.IntVal.getZExtValue() < Src1.IntVal.getBitWidth())
902    Dest.IntVal = Src1.IntVal.shl(Src2.IntVal.getZExtValue());
903  else
904    Dest.IntVal = Src1.IntVal;
905
906  SetValue(&I, Dest, SF);
907}
908
909void Interpreter::visitLShr(BinaryOperator &I) {
910  ExecutionContext &SF = ECStack.back();
911  GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
912  GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
913  GenericValue Dest;
914  if (Src2.IntVal.getZExtValue() < Src1.IntVal.getBitWidth())
915    Dest.IntVal = Src1.IntVal.lshr(Src2.IntVal.getZExtValue());
916  else
917    Dest.IntVal = Src1.IntVal;
918
919  SetValue(&I, Dest, SF);
920}
921
922void Interpreter::visitAShr(BinaryOperator &I) {
923  ExecutionContext &SF = ECStack.back();
924  GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
925  GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
926  GenericValue Dest;
927  if (Src2.IntVal.getZExtValue() < Src1.IntVal.getBitWidth())
928    Dest.IntVal = Src1.IntVal.ashr(Src2.IntVal.getZExtValue());
929  else
930    Dest.IntVal = Src1.IntVal;
931
932  SetValue(&I, Dest, SF);
933}
934
935GenericValue Interpreter::executeTruncInst(Value *SrcVal, Type *DstTy,
936                                           ExecutionContext &SF) {
937  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
938  IntegerType *DITy = cast<IntegerType>(DstTy);
939  unsigned DBitWidth = DITy->getBitWidth();
940  Dest.IntVal = Src.IntVal.trunc(DBitWidth);
941  return Dest;
942}
943
944GenericValue Interpreter::executeSExtInst(Value *SrcVal, Type *DstTy,
945                                          ExecutionContext &SF) {
946  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
947  IntegerType *DITy = cast<IntegerType>(DstTy);
948  unsigned DBitWidth = DITy->getBitWidth();
949  Dest.IntVal = Src.IntVal.sext(DBitWidth);
950  return Dest;
951}
952
953GenericValue Interpreter::executeZExtInst(Value *SrcVal, Type *DstTy,
954                                          ExecutionContext &SF) {
955  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
956  IntegerType *DITy = cast<IntegerType>(DstTy);
957  unsigned DBitWidth = DITy->getBitWidth();
958  Dest.IntVal = Src.IntVal.zext(DBitWidth);
959  return Dest;
960}
961
962GenericValue Interpreter::executeFPTruncInst(Value *SrcVal, Type *DstTy,
963                                             ExecutionContext &SF) {
964  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
965  assert(SrcVal->getType()->isDoubleTy() && DstTy->isFloatTy() &&
966         "Invalid FPTrunc instruction");
967  Dest.FloatVal = (float) Src.DoubleVal;
968  return Dest;
969}
970
971GenericValue Interpreter::executeFPExtInst(Value *SrcVal, Type *DstTy,
972                                           ExecutionContext &SF) {
973  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
974  assert(SrcVal->getType()->isFloatTy() && DstTy->isDoubleTy() &&
975         "Invalid FPTrunc instruction");
976  Dest.DoubleVal = (double) Src.FloatVal;
977  return Dest;
978}
979
980GenericValue Interpreter::executeFPToUIInst(Value *SrcVal, Type *DstTy,
981                                            ExecutionContext &SF) {
982  Type *SrcTy = SrcVal->getType();
983  uint32_t DBitWidth = cast<IntegerType>(DstTy)->getBitWidth();
984  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
985  assert(SrcTy->isFloatingPointTy() && "Invalid FPToUI instruction");
986
987  if (SrcTy->getTypeID() == Type::FloatTyID)
988    Dest.IntVal = APIntOps::RoundFloatToAPInt(Src.FloatVal, DBitWidth);
989  else
990    Dest.IntVal = APIntOps::RoundDoubleToAPInt(Src.DoubleVal, DBitWidth);
991  return Dest;
992}
993
994GenericValue Interpreter::executeFPToSIInst(Value *SrcVal, Type *DstTy,
995                                            ExecutionContext &SF) {
996  Type *SrcTy = SrcVal->getType();
997  uint32_t DBitWidth = cast<IntegerType>(DstTy)->getBitWidth();
998  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
999  assert(SrcTy->isFloatingPointTy() && "Invalid FPToSI instruction");
1000
1001  if (SrcTy->getTypeID() == Type::FloatTyID)
1002    Dest.IntVal = APIntOps::RoundFloatToAPInt(Src.FloatVal, DBitWidth);
1003  else
1004    Dest.IntVal = APIntOps::RoundDoubleToAPInt(Src.DoubleVal, DBitWidth);
1005  return Dest;
1006}
1007
1008GenericValue Interpreter::executeUIToFPInst(Value *SrcVal, Type *DstTy,
1009                                            ExecutionContext &SF) {
1010  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1011  assert(DstTy->isFloatingPointTy() && "Invalid UIToFP instruction");
1012
1013  if (DstTy->getTypeID() == Type::FloatTyID)
1014    Dest.FloatVal = APIntOps::RoundAPIntToFloat(Src.IntVal);
1015  else
1016    Dest.DoubleVal = APIntOps::RoundAPIntToDouble(Src.IntVal);
1017  return Dest;
1018}
1019
1020GenericValue Interpreter::executeSIToFPInst(Value *SrcVal, Type *DstTy,
1021                                            ExecutionContext &SF) {
1022  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1023  assert(DstTy->isFloatingPointTy() && "Invalid SIToFP instruction");
1024
1025  if (DstTy->getTypeID() == Type::FloatTyID)
1026    Dest.FloatVal = APIntOps::RoundSignedAPIntToFloat(Src.IntVal);
1027  else
1028    Dest.DoubleVal = APIntOps::RoundSignedAPIntToDouble(Src.IntVal);
1029  return Dest;
1030
1031}
1032
1033GenericValue Interpreter::executePtrToIntInst(Value *SrcVal, Type *DstTy,
1034                                              ExecutionContext &SF) {
1035  uint32_t DBitWidth = cast<IntegerType>(DstTy)->getBitWidth();
1036  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1037  assert(SrcVal->getType()->isPointerTy() && "Invalid PtrToInt instruction");
1038
1039  Dest.IntVal = APInt(DBitWidth, (intptr_t) Src.PointerVal);
1040  return Dest;
1041}
1042
1043GenericValue Interpreter::executeIntToPtrInst(Value *SrcVal, Type *DstTy,
1044                                              ExecutionContext &SF) {
1045  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1046  assert(DstTy->isPointerTy() && "Invalid PtrToInt instruction");
1047
1048  uint32_t PtrSize = TD.getPointerSizeInBits();
1049  if (PtrSize != Src.IntVal.getBitWidth())
1050    Src.IntVal = Src.IntVal.zextOrTrunc(PtrSize);
1051
1052  Dest.PointerVal = PointerTy(intptr_t(Src.IntVal.getZExtValue()));
1053  return Dest;
1054}
1055
1056GenericValue Interpreter::executeBitCastInst(Value *SrcVal, Type *DstTy,
1057                                             ExecutionContext &SF) {
1058
1059  Type *SrcTy = SrcVal->getType();
1060  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1061  if (DstTy->isPointerTy()) {
1062    assert(SrcTy->isPointerTy() && "Invalid BitCast");
1063    Dest.PointerVal = Src.PointerVal;
1064  } else if (DstTy->isIntegerTy()) {
1065    if (SrcTy->isFloatTy()) {
1066      Dest.IntVal = APInt::floatToBits(Src.FloatVal);
1067    } else if (SrcTy->isDoubleTy()) {
1068      Dest.IntVal = APInt::doubleToBits(Src.DoubleVal);
1069    } else if (SrcTy->isIntegerTy()) {
1070      Dest.IntVal = Src.IntVal;
1071    } else
1072      llvm_unreachable("Invalid BitCast");
1073  } else if (DstTy->isFloatTy()) {
1074    if (SrcTy->isIntegerTy())
1075      Dest.FloatVal = Src.IntVal.bitsToFloat();
1076    else
1077      Dest.FloatVal = Src.FloatVal;
1078  } else if (DstTy->isDoubleTy()) {
1079    if (SrcTy->isIntegerTy())
1080      Dest.DoubleVal = Src.IntVal.bitsToDouble();
1081    else
1082      Dest.DoubleVal = Src.DoubleVal;
1083  } else
1084    llvm_unreachable("Invalid Bitcast");
1085
1086  return Dest;
1087}
1088
1089void Interpreter::visitTruncInst(TruncInst &I) {
1090  ExecutionContext &SF = ECStack.back();
1091  SetValue(&I, executeTruncInst(I.getOperand(0), I.getType(), SF), SF);
1092}
1093
1094void Interpreter::visitSExtInst(SExtInst &I) {
1095  ExecutionContext &SF = ECStack.back();
1096  SetValue(&I, executeSExtInst(I.getOperand(0), I.getType(), SF), SF);
1097}
1098
1099void Interpreter::visitZExtInst(ZExtInst &I) {
1100  ExecutionContext &SF = ECStack.back();
1101  SetValue(&I, executeZExtInst(I.getOperand(0), I.getType(), SF), SF);
1102}
1103
1104void Interpreter::visitFPTruncInst(FPTruncInst &I) {
1105  ExecutionContext &SF = ECStack.back();
1106  SetValue(&I, executeFPTruncInst(I.getOperand(0), I.getType(), SF), SF);
1107}
1108
1109void Interpreter::visitFPExtInst(FPExtInst &I) {
1110  ExecutionContext &SF = ECStack.back();
1111  SetValue(&I, executeFPExtInst(I.getOperand(0), I.getType(), SF), SF);
1112}
1113
1114void Interpreter::visitUIToFPInst(UIToFPInst &I) {
1115  ExecutionContext &SF = ECStack.back();
1116  SetValue(&I, executeUIToFPInst(I.getOperand(0), I.getType(), SF), SF);
1117}
1118
1119void Interpreter::visitSIToFPInst(SIToFPInst &I) {
1120  ExecutionContext &SF = ECStack.back();
1121  SetValue(&I, executeSIToFPInst(I.getOperand(0), I.getType(), SF), SF);
1122}
1123
1124void Interpreter::visitFPToUIInst(FPToUIInst &I) {
1125  ExecutionContext &SF = ECStack.back();
1126  SetValue(&I, executeFPToUIInst(I.getOperand(0), I.getType(), SF), SF);
1127}
1128
1129void Interpreter::visitFPToSIInst(FPToSIInst &I) {
1130  ExecutionContext &SF = ECStack.back();
1131  SetValue(&I, executeFPToSIInst(I.getOperand(0), I.getType(), SF), SF);
1132}
1133
1134void Interpreter::visitPtrToIntInst(PtrToIntInst &I) {
1135  ExecutionContext &SF = ECStack.back();
1136  SetValue(&I, executePtrToIntInst(I.getOperand(0), I.getType(), SF), SF);
1137}
1138
1139void Interpreter::visitIntToPtrInst(IntToPtrInst &I) {
1140  ExecutionContext &SF = ECStack.back();
1141  SetValue(&I, executeIntToPtrInst(I.getOperand(0), I.getType(), SF), SF);
1142}
1143
1144void Interpreter::visitBitCastInst(BitCastInst &I) {
1145  ExecutionContext &SF = ECStack.back();
1146  SetValue(&I, executeBitCastInst(I.getOperand(0), I.getType(), SF), SF);
1147}
1148
1149#define IMPLEMENT_VAARG(TY) \
1150   case Type::TY##TyID: Dest.TY##Val = Src.TY##Val; break
1151
1152void Interpreter::visitVAArgInst(VAArgInst &I) {
1153  ExecutionContext &SF = ECStack.back();
1154
1155  // Get the incoming valist parameter.  LLI treats the valist as a
1156  // (ec-stack-depth var-arg-index) pair.
1157  GenericValue VAList = getOperandValue(I.getOperand(0), SF);
1158  GenericValue Dest;
1159  GenericValue Src = ECStack[VAList.UIntPairVal.first]
1160                      .VarArgs[VAList.UIntPairVal.second];
1161  Type *Ty = I.getType();
1162  switch (Ty->getTypeID()) {
1163    case Type::IntegerTyID: Dest.IntVal = Src.IntVal;
1164    IMPLEMENT_VAARG(Pointer);
1165    IMPLEMENT_VAARG(Float);
1166    IMPLEMENT_VAARG(Double);
1167  default:
1168    dbgs() << "Unhandled dest type for vaarg instruction: " << *Ty << "\n";
1169    llvm_unreachable(0);
1170  }
1171
1172  // Set the Value of this Instruction.
1173  SetValue(&I, Dest, SF);
1174
1175  // Move the pointer to the next vararg.
1176  ++VAList.UIntPairVal.second;
1177}
1178
1179GenericValue Interpreter::getConstantExprValue (ConstantExpr *CE,
1180                                                ExecutionContext &SF) {
1181  switch (CE->getOpcode()) {
1182  case Instruction::Trunc:
1183      return executeTruncInst(CE->getOperand(0), CE->getType(), SF);
1184  case Instruction::ZExt:
1185      return executeZExtInst(CE->getOperand(0), CE->getType(), SF);
1186  case Instruction::SExt:
1187      return executeSExtInst(CE->getOperand(0), CE->getType(), SF);
1188  case Instruction::FPTrunc:
1189      return executeFPTruncInst(CE->getOperand(0), CE->getType(), SF);
1190  case Instruction::FPExt:
1191      return executeFPExtInst(CE->getOperand(0), CE->getType(), SF);
1192  case Instruction::UIToFP:
1193      return executeUIToFPInst(CE->getOperand(0), CE->getType(), SF);
1194  case Instruction::SIToFP:
1195      return executeSIToFPInst(CE->getOperand(0), CE->getType(), SF);
1196  case Instruction::FPToUI:
1197      return executeFPToUIInst(CE->getOperand(0), CE->getType(), SF);
1198  case Instruction::FPToSI:
1199      return executeFPToSIInst(CE->getOperand(0), CE->getType(), SF);
1200  case Instruction::PtrToInt:
1201      return executePtrToIntInst(CE->getOperand(0), CE->getType(), SF);
1202  case Instruction::IntToPtr:
1203      return executeIntToPtrInst(CE->getOperand(0), CE->getType(), SF);
1204  case Instruction::BitCast:
1205      return executeBitCastInst(CE->getOperand(0), CE->getType(), SF);
1206  case Instruction::GetElementPtr:
1207    return executeGEPOperation(CE->getOperand(0), gep_type_begin(CE),
1208                               gep_type_end(CE), SF);
1209  case Instruction::FCmp:
1210  case Instruction::ICmp:
1211    return executeCmpInst(CE->getPredicate(),
1212                          getOperandValue(CE->getOperand(0), SF),
1213                          getOperandValue(CE->getOperand(1), SF),
1214                          CE->getOperand(0)->getType());
1215  case Instruction::Select:
1216    return executeSelectInst(getOperandValue(CE->getOperand(0), SF),
1217                             getOperandValue(CE->getOperand(1), SF),
1218                             getOperandValue(CE->getOperand(2), SF));
1219  default :
1220    break;
1221  }
1222
1223  // The cases below here require a GenericValue parameter for the result
1224  // so we initialize one, compute it and then return it.
1225  GenericValue Op0 = getOperandValue(CE->getOperand(0), SF);
1226  GenericValue Op1 = getOperandValue(CE->getOperand(1), SF);
1227  GenericValue Dest;
1228  Type * Ty = CE->getOperand(0)->getType();
1229  switch (CE->getOpcode()) {
1230  case Instruction::Add:  Dest.IntVal = Op0.IntVal + Op1.IntVal; break;
1231  case Instruction::Sub:  Dest.IntVal = Op0.IntVal - Op1.IntVal; break;
1232  case Instruction::Mul:  Dest.IntVal = Op0.IntVal * Op1.IntVal; break;
1233  case Instruction::FAdd: executeFAddInst(Dest, Op0, Op1, Ty); break;
1234  case Instruction::FSub: executeFSubInst(Dest, Op0, Op1, Ty); break;
1235  case Instruction::FMul: executeFMulInst(Dest, Op0, Op1, Ty); break;
1236  case Instruction::FDiv: executeFDivInst(Dest, Op0, Op1, Ty); break;
1237  case Instruction::FRem: executeFRemInst(Dest, Op0, Op1, Ty); break;
1238  case Instruction::SDiv: Dest.IntVal = Op0.IntVal.sdiv(Op1.IntVal); break;
1239  case Instruction::UDiv: Dest.IntVal = Op0.IntVal.udiv(Op1.IntVal); break;
1240  case Instruction::URem: Dest.IntVal = Op0.IntVal.urem(Op1.IntVal); break;
1241  case Instruction::SRem: Dest.IntVal = Op0.IntVal.srem(Op1.IntVal); break;
1242  case Instruction::And:  Dest.IntVal = Op0.IntVal & Op1.IntVal; break;
1243  case Instruction::Or:   Dest.IntVal = Op0.IntVal | Op1.IntVal; break;
1244  case Instruction::Xor:  Dest.IntVal = Op0.IntVal ^ Op1.IntVal; break;
1245  case Instruction::Shl:
1246    Dest.IntVal = Op0.IntVal.shl(Op1.IntVal.getZExtValue());
1247    break;
1248  case Instruction::LShr:
1249    Dest.IntVal = Op0.IntVal.lshr(Op1.IntVal.getZExtValue());
1250    break;
1251  case Instruction::AShr:
1252    Dest.IntVal = Op0.IntVal.ashr(Op1.IntVal.getZExtValue());
1253    break;
1254  default:
1255    dbgs() << "Unhandled ConstantExpr: " << *CE << "\n";
1256    llvm_unreachable(0);
1257    return GenericValue();
1258  }
1259  return Dest;
1260}
1261
1262GenericValue Interpreter::getOperandValue(Value *V, ExecutionContext &SF) {
1263  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
1264    return getConstantExprValue(CE, SF);
1265  } else if (Constant *CPV = dyn_cast<Constant>(V)) {
1266    return getConstantValue(CPV);
1267  } else if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
1268    return PTOGV(getPointerToGlobal(GV));
1269  } else {
1270    return SF.Values[V];
1271  }
1272}
1273
1274//===----------------------------------------------------------------------===//
1275//                        Dispatch and Execution Code
1276//===----------------------------------------------------------------------===//
1277
1278//===----------------------------------------------------------------------===//
1279// callFunction - Execute the specified function...
1280//
1281void Interpreter::callFunction(Function *F,
1282                               const std::vector<GenericValue> &ArgVals) {
1283  assert((ECStack.empty() || ECStack.back().Caller.getInstruction() == 0 ||
1284          ECStack.back().Caller.arg_size() == ArgVals.size()) &&
1285         "Incorrect number of arguments passed into function call!");
1286  // Make a new stack frame... and fill it in.
1287  ECStack.push_back(ExecutionContext());
1288  ExecutionContext &StackFrame = ECStack.back();
1289  StackFrame.CurFunction = F;
1290
1291  // Special handling for external functions.
1292  if (F->isDeclaration()) {
1293    GenericValue Result = callExternalFunction (F, ArgVals);
1294    // Simulate a 'ret' instruction of the appropriate type.
1295    popStackAndReturnValueToCaller (F->getReturnType (), Result);
1296    return;
1297  }
1298
1299  // Get pointers to first LLVM BB & Instruction in function.
1300  StackFrame.CurBB     = F->begin();
1301  StackFrame.CurInst   = StackFrame.CurBB->begin();
1302
1303  // Run through the function arguments and initialize their values...
1304  assert((ArgVals.size() == F->arg_size() ||
1305         (ArgVals.size() > F->arg_size() && F->getFunctionType()->isVarArg()))&&
1306         "Invalid number of values passed to function invocation!");
1307
1308  // Handle non-varargs arguments...
1309  unsigned i = 0;
1310  for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
1311       AI != E; ++AI, ++i)
1312    SetValue(AI, ArgVals[i], StackFrame);
1313
1314  // Handle varargs arguments...
1315  StackFrame.VarArgs.assign(ArgVals.begin()+i, ArgVals.end());
1316}
1317
1318
1319void Interpreter::run() {
1320  while (!ECStack.empty()) {
1321    // Interpret a single instruction & increment the "PC".
1322    ExecutionContext &SF = ECStack.back();  // Current stack frame
1323    Instruction &I = *SF.CurInst++;         // Increment before execute
1324
1325    // Track the number of dynamic instructions executed.
1326    ++NumDynamicInsts;
1327
1328    DEBUG(dbgs() << "About to interpret: " << I);
1329    visit(I);   // Dispatch to one of the visit* methods...
1330#if 0
1331    // This is not safe, as visiting the instruction could lower it and free I.
1332DEBUG(
1333    if (!isa<CallInst>(I) && !isa<InvokeInst>(I) &&
1334        I.getType() != Type::VoidTy) {
1335      dbgs() << "  --> ";
1336      const GenericValue &Val = SF.Values[&I];
1337      switch (I.getType()->getTypeID()) {
1338      default: llvm_unreachable("Invalid GenericValue Type");
1339      case Type::VoidTyID:    dbgs() << "void"; break;
1340      case Type::FloatTyID:   dbgs() << "float " << Val.FloatVal; break;
1341      case Type::DoubleTyID:  dbgs() << "double " << Val.DoubleVal; break;
1342      case Type::PointerTyID: dbgs() << "void* " << intptr_t(Val.PointerVal);
1343        break;
1344      case Type::IntegerTyID:
1345        dbgs() << "i" << Val.IntVal.getBitWidth() << " "
1346               << Val.IntVal.toStringUnsigned(10)
1347               << " (0x" << Val.IntVal.toStringUnsigned(16) << ")\n";
1348        break;
1349      }
1350    });
1351#endif
1352  }
1353}
1354